The present disclosure herein relates to an ion generating apparatus, and a treating apparatus and a treating method using the same to remove a tumor.
As radiation treating methods, there are X-ray, electron beam, and ion beam treating methods, and the like. Since the X-ray treating method is an inexpensive method which may be embodied by using a simple apparatus, the X-ray treating method is universally used among the radiation treating methods. Treating of a tumor in the case where electrons are accelerated by an accelerator to be injected into the tumor was proved in 1950s. However, the electron beam treatment settled as a method of radiation treatment in earnest by realizing a size reduction of an electron accelerator in 1980s. Meanwhile, the X-ray treatment or electron beam treatment breaks a hydrogen bond in a cancer cell to destroy DNA of a cancer, which entails a side effect of seriously damaging healthy cells existing on a progress path. As a method for reducing a limitation of exposure to normal cells, a technology such as intensity-modulated radiation therapy (IMRT), tomo-therapy, and cyber knife has been developed, but these did not completely solve the aforementioned side effect.
The ion beam treating method receives attention as treating means for reducing the side effect of the X-ray treatment or the electron beam treatment. An ion beam should be accelerated to have a high speed like the electrons in order to permeate a material. Even though the speed of the ion beam is gradually reduced in the case where the ion beam permeates a predetermined material, immediately before the ion beam is stopped, the largest energy loss of ionizing radiation occurs. This phenomenon is called a Bragg peak named for William Henry Bragg finding this in 1903. Therefore, in the case of the ion beam treating method, when the speed of the ions is precisely controlled, selective and local treatment to malignant tumors is feasible. In the case where the tumor is positioned deeply in the body, protons or ions having very high energy should be accelerated from the outside of the body. Among methods for accelerating the protons or ions, there is a laser driven ion acceleration method. If high power laser beam is irradiated on a thin film, ions or protons of the thin film escape with acceleration energy to the outside of the thin film by a target normal sheath acceleration model (TNSA model) or a radiation pressure acceleration model (RPA model). The escaping ions permeate a patient's body by energy of the ions, and are stopped at a predetermined depth at which the tumor is positioned, and active oxygen (free oxygen radical) is generated in a large amount in a stop area to necrotize the tumor cells. This is a typical ion beam treating principle.
In the ion beam treating method using the laser driven ion acceleration method, two properties are required in the ions. In order to inject the ions deeply into the body, it is required that the ions are charged particles in a high energy state and the most charged particles have the same energy. As an example, protons having energy of about 250 MeV may permeate a human body by about 20 cm. In the case of ocular cancer treatment, charged particles having high energy of about 70 MeV are required, and in order to treat a cancer positioned deeply in the body, charged particles having high energy of about 200 MeV or more are required. In this case, the protons and the ions driven by the laser should have uniform energy.